OXYGEN REDUCTION REACTION CATALYST
A method for the manufacture of an oxygen reduction reaction (ORR) catalyst, the method comprising; providing a metal organic framework (MOF) material having a specific internal pore volume of 0.7 cm 3 g −1 or greater; providing a source of iron and/or cobalt; pyrolysing the MOF material together with the source of iron and/or cobalt to form the catalyst, wherein the MOF material comprises nitrogen and/or the MOF material is pyrolysed together with a source of nitrogen and the source of iron and/or cobalt is disclosed.
1 . A method for the manufacture of an oxygen reduction reaction (ORR) catalyst, the method comprising;
providing a metal organic framework (MOF) material having an isotropic cavity shape with a largest cavity size of 12 Å or greater;
providing a source of iron and/or cobalt;
pyrolysing the MOF material together with the source of iron and/or cobalt to form the catalyst,
wherein the MOF material comprises nitrogen and/or the MOF material is pyrolysed together with a source of nitrogen and the source of iron and/or cobalt.
2 . A method according to claim 1 , wherein the MOF material comprises a transition metal selected from Zn, Mg, Cu, Ag, and Ni, or a combination of two or more thereof.
3 . A method according to claim 1 , wherein the transition metal comprises zinc.
4 . A method according to claim 1 , wherein the MOF material is a Zeolitic Imidazolate Framework (ZIF) material.
5 . A method according to claim 1 , wherein the source of iron and/or cobalt is a salt of iron and/or cobalt.
6 . A method according to claim 1 , wherein the pyrolysis of the MOF material is conducted at a temperature from 700 to 1500° C.
7 . A method according to claim 1 , wherein the source of nitrogen comprises a nitrogen-containing ligand, preferably 1,10-phenanthroline.
8 . A method according to claim 1 , wherein the pyrolysis is conducted under an atmosphere comprising, argon, nitrogen, ammonia, or hydrogen, or mixtures thereof.
9 . A method according to claim 1 , wherein the pyrolysis is conducted in two steps, a first step under an inert atmosphere and a second step under an atmosphere comprising ammonia, hydrogen, carbon dioxide and/or carbon monoxide.
10 . A method according to claim 1 , wherein the MOF material has an average crystal size with a longest size of 200 nm or less.
11 . A method according to claim 1 , wherein the MOF material is provided on an electrically conducting support.
12 . A method according to claim 1 , wherein the MOF material has a specific internal pore volume of 0.7 cm 3 g −1 or greater.
13 . A method for the manufacture of an oxygen reduction reaction (ORR) catalyst, the method comprising:
providing a metal organic framework (MOF) ligand and MOF metal source;
providing a source of iron and/or cobalt;
optionally providing a source of nitrogen;
providing a source of energy sufficient to provide a catalyst precursor comprising a MOF material having an isotropic cavity shape with a largest cavity size of 12 Å or greater;
and pyrolysing the catalyst precursor to provide the ORR catalyst.
14 . An ORR catalyst that is made according to the method of claim 1 .
15 . An ORR catalyst that is made according to the method of claim 13 .
16 . A method according to claim 1 , wherein the method further comprises forming an ink composition comprising the catalyst and a polymer.
17 . A method according to claim 13 , wherein the method further comprises forming an ink composition comprising the catalyst and a polymer.
18 . An ink composition that is made according to the method of claim 16 .
19 . An ink composition that is made according to the method of claim 17 .
20 . A cathode electrode for a fuel cell comprising the ORR catalyst of claim 14 .
21 . A cathode electrode for a fuel cell comprising the ORR catalyst of claim 15 .